"Do not put a finger IN the ear...."
What Richard said - around rather than in your ear.
It's an extremely old and widespread technique and has been practiced by singers throughout the world for many centuries, probably millenia.
There are woodcuts and illustrations of all types of singers using it, including muezzins calling the faithful to prayer from the top of minarets.
It was still being used by Travellers selling 'the ballads' (song sheets) up to the 1950s, who sang the songs they were selling at noisy fairs and markets in the first half of the twentieth century
It's a great device for keeping in tune and maintaining your pitch while singing unaccompanied.
Bert Lloyd said it was popular with Eastern European singers when he was collecting there; he and MacColl probably introduced it to the British folk song revival.
The problem with using it today is that finger-in-ear is often used as a term of abuse to denigrate those who take folk song seriously - usually by tone-deaf morons who would probably describe Wagner as a 'folk composer'
Jim Carroll